2m sales of original justify Prototype 2

Given the mixed reviews for the original Prototype, a sequel perhaps wasn't a foregone conclusion. However, once it sold two million copies, the recently announced follow-up became inevitable, developer Radical Entertainment has revealed.

"When Prototype surpassed 2MM units we knew gamers would want a sequel to find out what happens next with Alex Mercer," said Radical Entertainment boss Ken Rosman.

"The team here at Radical is sincerely grateful to the fans and we are laser focused on delivering an even bigger and better experience with Prototype 2!"

Radical's sequel, due for release in 2012, follows Sgt. James Heller as he attempts to destroy the original game's anti-hero Alex Mercer. Take a look at the reveal trailer below for a closer look

The developer also announced that the first game in its superhero franchise is now available on Xbox Live's Games on Demand service, priced £19.99. It'll be hitting PlayStation Network tomorrow too, for the same price.